Why do clustering options sometimes change?
Available clustering options are based on the source databases of the imported documents. For example, the option to cluster using Technology Indicators is available only when documents from CAplus, USPATFULL, and USPAT2 are source databases. Technology Indicators are CAS indexing terms that are only available in documents from CAplus, and in chemistry-relevant USPATFULL and USPAT2 documents that have been enhanced with this indexing.